Archive

Ephemeris for Friday, June 29th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:32, and it will rise tomorrow at 6:00. The Moon, 1 day past full, will rise at 10:38 this evening.

Lets preview July’s skies. The Sun, having reached its northern solstice, is beginning to slide southward again, at first imperceptibly, then with greater speed. The daylight hours will decrease from 15 hours and 30 minutes Sunday to 14 hours 41 minutes at month’s end. The daylight hours will be slightly shorter south of Interlochen, and slightly longer to the north. The altitude of the Sun at local noon, when the Sun is due south will decrease from 68 degrees today to 63 degrees at month’s end. The Sun will be a degree lower in the Straits area. Despite the warmth, the Earth will reach its greatest distance from the Sun on Friday the 6th. The planets visible this month in the evening are Venus, Jupiter, Saturn and later, Mars.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

July Evening Star Chart

Star Chart for July 2018 (11 p.m. EDT July 15, 2018). Created using my LookingUp program. Click on image to enlarge.

The planets and stars are plotted for the 15th at 11 p.m. EDT in the evening and 4:30 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian. (An hour 45 minutes behind our daylight saving time meridian during EDT). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes earlier than the current time.

Note the chart times of 11 p.m. and 4:30 a.m. are for the 15th. For each week before the 15th add ½ hour (28 minutes if you’re picky). For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog. For planet positions on dates other than the 15th, check the Wednesday planet posts on this blog.

July Morning Star Chart

Star Chart for July 2018 mornings based on 4:30 a.m. July 15th. Created using my LookingUp program. Click on image to enlarge.

For a list of constellation names to go with the abbreviations click here.

Star chart annotations

Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.

Leaky Big Dipper drips on Leo.

Follow the arc of the handle of the Big Dipper to the star Arcturus and

Continue with a spike to Spica.

The Summer Triangle is in red.

DAqR – Delta Aquariid meteor shower radiant

Twilight

Evening nautical twilight ends at 11:00 p.m. EDT on the 1st, decreasing to 10:28 p.m. EDT on the 31st.
Evening astronomical twilight ends at 12:03 a.m. EDT on the 1st, decreasing to 11:28 a.m. EDT on the 31st.
Morning astronomical twilight starts at 3:38 a.m. EDT on the 1st, and increasing to 4:28 a.m. EDT on the 31st.
Morning nautical twilight starts at 4:41 a.m. EDT on the 1st, and increasing to 5:17 a.m. EDT on the 31st.

Ephemeris for Thursday, June 28th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:32, and it will rise tomorrow at 6:00. The Moon, at full today, will rise at 9:54 this evening.

Just before midnight last night Saturn was in opposition to the Sun. We’re not talking about an argument here. To the astronomer opposition simply means that a planet, in this case Saturn, is 180 degrees from the Sun, or opposite the Sun in the sky. It is a time when the planet rises at sunset and sets at sunrise. It is also a time when the planet is around its closest to the Earth. It’s not a big deal for Saturn, which is almost 10 times farther from the Sun than we are. However it is a big deal for a nearby planet like Mars, which at the end of July will be closer to us than at any time since 2003, at 35.8 million miles. That’s a big deal since Mars is a small planet, a bit more than half the size of the Earth.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The apparent sizes of Saturn and Mars as seen from the Earth at opposition and solar conjunction. All at the same scale. Created using Cartes du Ciel (Sky Charts).

Wednesday, June 27th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, 1 day before full, will set at 6:27 tomorrow morning.

It’s Wednesday again and time to look for and at the bright planets. Three of them are in the evening sky. The brilliant beacon of Venus will be visible in the western twilight from about 9:50 p.m. until it sets at 11:53 p.m. Mercury is far below and right of it, setting at 10:59 p.m. Jupiter will be in the south as it gets dark. Jupiter is only outshone by Venus and the Moon, though Mars will outshine it next month at its closest. Jupiter will set at 3:05 a.m. Binoculars will show it to be bigger than star-like in size. Saturn which is opposite the Sun in the sky today will rise as the Sun sets. It’s right below the Moon tonight. Mars will rise at 11:39 p.m. and is now outshining Saturn.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Venus and Mercury low in the western sky ay 10 p.m. June 27, 2018. Click on image to enlarge. Created using Stellarium.

Telescopic appearance of Venus on June 27, 2018. A moon filter helps cut down the glare to be able to more easily see the phase. Created using Stellarium.

Jupiter, Saturn and the Moon tonight at 10:30 p.m. on June 27, 2018. Click on the image to enlarge. Created using Stellarium.

The Moon and Saturn as they might appear in binoculars at 10:30 p.m. June 27, 2018. Created using Stellarium.

Jupiter and Saturn with the same magnification at 10:30 p.m. June 27, 2018. Information on Europa events and the Great Red Spot is below. Created using Cartes du Ciel (Sky Charts).

Mars, Saturn and the Moon at 5 a.m. June 28, 2018. Click on the image to enlarge. Created using Stellarium.

Greatly enlarged telescopic Mars at 5 a.m. June 28, 2018. Note that the dark albedo features may be covered by a global dust storm currently raging on the Red Planet. Created using Cartes du Ciel (Sky Charts).

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on June 27, 2018. The night ends on the left with sunrise on the 28th. Click on the image to enlarge. Created using my LookingUp program.

Ephemeris for Tuesday, June 26th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, 2 days before full, will set at 5:42 tomorrow morning.

Today is the day of the latest sunset, at least for around latitude 45 degrees north. It will be within the same minute for the next 5 days, before it retreats. By the end of July sunset will be at 9:09 p.m. The lopsidedness of the dates of earliest sunrise and latest sunset is caused by two factors. The Sun’s high latitude or declination above the equator, which makes it appear to move faster, countered in the summer by the fact that the Earth is almost at its farthest from the Sun, which makes it appear to be slower. These effects are why sundials don’t keep proper clock time without the adjustment of the equation of time to the readout, or fancy sundials that take that into account.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Ephemeris for Monday, June 25th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:58. The Moon, 3 days before full, will set at 5:02 tomorrow morning.

A recent post of Dr. Phil Plait’s Bad Astronomy Blog caught my eye. The object discovered is being called Andromeda’s Parachute. It has three relatively bright star-like points arranged in an arc like a parachute canopy, with another star-like point beneath it as the parachutist. It is the light from a single quasar, an active galaxy nucleus being split up by the gravitational lens of a closer, but dimmer galaxy in between us and the quasar. It’s very beautiful, and within reach of only the biggest telescopes. It was discovered using the Pan-STARRS telescope on Haleakala in Maui by George Nelson.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Quadruple quasar dubbed Andromeda’s parachute. The four images (A-D) of the quadruply lensed quasar J014709+463037 can be seen in this deep image taken by the Pan-STARRS telescope. The lensing galaxy (G) is marked by an X. Credit: Berghea et al.

I’m hoping to be out there and set up before 9 p.m. It’s a planet fest of sorts with Venus, Jupiter and Saturn plus a nearly full Moon. Sorry, Mars won’t rise till nearly midnight. Dress warmly, it’s supposed to get down into the 50’s, and with a north wind, may seem even colder.

This is a reprint of “Mars Summer” which I wrote for the Grand Traverse Astronomical Society newsletter Stellar Sentinel’s June 2018 issue.

The planet Mars has oppositions from the Sun about every 26 months more or less. These oppositions are a time when Mars is closest to the Earth for its position in orbit. It’s distance at these times range from 34.6 to almost 63 million miles, a range of almost 2 to 1. This is because Mars has a very elliptical orbit as can be seen below.

Mars closest approaches to the Earth from August 27, 2003 to July 31, 2018. Diagram created using Bob Moler’s LookingUp program.

Especially close approaches to the Earth occur every 15 or 17 years in the latter half of summer in those years. My first close approach was September 7, 1956. It was a famous one for the time. Professional astronomers of that time were pretty sure that Mars didn’t have canals, features that were ‘discovered’ by Giovanni Schiaparelli in 1877. To him the features were grooves or channels. Unfortunately the Italian word for them was canali. The world press proclaimed that there were “canals” on Mars. Canals by definition are artificial and require canal builders, Martians by inference.

Like I said, professional astronomers had discounted them by 1956. But science fiction read by young impressionable amateur astronomers like myself talked about old races of Martians hoarding every last drop of water. So maybe we believed. With my 5 inch reflector I observed the polar cap and the large dark feature Syrtis Major.

My next close approach of Mars was August 12, 1971. That summer I was working out of town and in the midst of a move from Grand Rapids to Traverse City, so was unable to observe Mars properly.

In the summer and autumn of 1973 I was able to do an observing program of Mars when it was almost as close as in 1971, drawing its features. I found out that to really observe a planet it takes time to educate the eye and brain to see faint, fuzzy detail. And since I didn’t believe in canals by this time, I didn’t see them.

The next close approach was September 22, 1988. The first “Mars Night” held by the society. We had a great turnout. But Mars was tiny as seen in telescopes. At best it was 23.81 seconds of arc in diameter. The Moon and Sun are about 1,800 seconds in diameter. It would be a bit larger than half the apparent diameter of Jupiter at average distance.

On August 27, 2003 Mars came closer than at any time in 50,000 years some astronomers said. The society held its second “Mars Night” at the Rogers Observatory, and wow, the lines of people ran down the drive and onto the shoulder of the road. As in 1988, I was stationed on the lawn at the front of the observatory with the portable Celestron 11 telescope, which actually gave clearer views than the 14 inch telescope in the dome. (Hot bodies in dome make for lousy seeing.)

2003 is also memorable or rather infamous for the “Mars Hoax” email. Proclaiming that Mars would appear as large as the Moon on August 27th. This hoax has been propagated every two years since. I expect 2018 to be a banner year for the resurrection of the hoax.

We come to this year, 2018, 15 years after the 2003 closest approach. Mars will reach opposition on July 27th. It’s closest approach to the Earth will be on July 31st, at the distance of 35,784,000 miles. The reason the dates aren’t the same is that Mars will still be a month before reaching perihelion, its closest to the Sun, so it’s getting even closer than at the time of opposition.

The Mars oppositions of October 2020, December 2022, January 2025 and February 2027 will be of increasing distances up to 63.0 million miles. This will be followed by oppositions of decreasing distances in March 2029, May 2031, and July 2033 leading to another close approach on September 11, 3035 at 35.4 million miles.

However by 2035 there may be humans on Mars waving back at us. It’s odd that anyone on Mars at the time probably wouldn’t be able to see the Earth at that time. Martian oppositions for us, are the time of inferior conjunctions of Earth with the Sun. We’d be lost in the Sun’s glare.
For the very closest views of Mars get on the Internet and search for Mars Curiosity, Mars Opportunity and Mars Hirise. No telescope required.